U.S. Pat. No. 3,985,118 discloses a solar furnace wherein multiple Fresnel lenses focus light rays upon heat conductors associated with each of the lenses. Each heat conductor has an exposed arcuate portion which serves to mount lens supporting means permitting pivotal movement of the supporting means about the conductor to maintain the lens focus in common with a portion of the conductor. Fluid passing through the vessels is heated to the extent that it may be used for powering a steam turbine associated with an electrical generator. To provide a self-contained, transportable generating system the solar furnace may be incorporated into a structure mounting additional components providing for condensation of the steam and recirculation to the solar furnace vessels.
U.S. Pat. No. 3,991,741 discloses an array of linear lenses, used as a combination roof-skylight-solar collector. The lenses are oriented at a given latitude to face the most remote of the earth's poles inclined by the local latitude angle. Moving absorbers are used to receive the sunlight at the focal spot of each lens. The absorbers move back and forth during the day as the sun's position changes, causing the focal spots to move.
U.S. Pat. No. 4,058,110 discloses a cylindrical reflector or lens, used under aberrated conditions in conjunction with an enlarged primary collector to obtain wide angle scanning performance that will allow concentration of solar radiation without extensive tracking. The cylindrical reflectors or lenses operate under aberrated conditions in conjunction with an enlarged primary collector to produce scanning properties that allow for the tracking of the sun for extended periods of time with no mechanical motion.
One type of solar air heater includes a housing having a transparent front wall, an inlet and outlet for establishing a flow path for air to be heated, and a porous radiation absorbent collector plate positioned across the flow path and arranged to accept incident solar radiation passing through the front wall. A radiation trap is placed inside the housing either adjacent to the front wall, directly on top of the collector plate, or between the collector plate and the front wall. The radiation trap has a cellular or “honeycomb” structure and is made from a material which is light-transmitting but opaque to infrared radiation.
Another solar radiation collector employs a dual flow path relative to heat transfer surfaces of the collector panel. A major air flow is confined beneath the panel, but a subsidiary (bypass) air flow at an angle to the principal air flow is employed to suppress natural (free) flow convection at an upper side of the panel. The subsidiary air flow can be established by perforations in the collector panel and by creation of a suction for the bypass air. Energy collection is further enhanced by the use of a collector panel having a low thermal mass and providing good thermal interchange with a relatively small air mass moving beneath and above the panel, while being arranged to limit thermal conduction along the panel in the direction of air flow. Thus, a thermal gradient is established along the length of the collector panel, with a low temperature differential with the heated air mass at every position, with a fast heating response time and minimized reradiation losses. Examples of such gradient “solar traps” that facilitate incoming radiation and prevent long wave infra-red reradiation are provided in Union Carbide's U.S. Pat. No. 4,262,657 and Knöös U.S. Pat. No. 4,054,124.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.